In recent years, the number of deliveries of frozen products requiring cold insulation has been increasing with popularization of frozen food. Generally, such deliveries are classified into a bulk delivery from a factory of frozen products to wholesalers (distribution centers), and a small cargo delivery from a wholesaler to supermarkets or convenience stores.
In the small cargo delivery from a wholesaler to supermarkets or convenience stores, frozen products are classified and housed in cold-insulating containers for each destination.
Many of conventional cold-insulating containers employ a single heat-insulating material, such as expanded polystyrene and rigid urethane foam, and zippers or hook-and-loop fasteners for opening and closing the lids thereof. However, for such a cold-insulating container, the heat-insulating material thereof is excellent in initial thermal conductivity and poor in cold-insulating performance. Additionally, the cold-insulating container is likely to be bulky in transportation and storage after delivery. To address this problem, a collapsible cold-insulating vessel having improved cold-insulating performance has been developed. Such a technique is disclosed in Japanese Patent Unexamined Publication No. 2003-112786.
FIG. 11 is a perspective view showing a cold-insulating vessel disclosed in Japanese Patent Unexamined Publication No. 2003-112786. Heat-insulating vessel 100 disclosed in Japanese Patent Unexamined Publication No. 2003-112786 is made of flexible outer bag 101 and inner bag 103, and vacuum heat-insulating panels 102. For outer bag 101, five faces, i.e. a bottom face and four side faces thereof are sewn into substantially a rectangular parallelepiped, and belt 105 is placed from a side face over the bottom face to the opposite side face. Additionally, onto one of upper sides of outer bag 101, lid 104 is sewn. On the bottom of outer bag 101 and inside of lid 104, heat-insulating panels (not shown) are previously provided.
Prior to use, four heat-insulating panels 102 are inserted along the four side faces of outer bag 101, and hook-and-loop fasteners 111 on respective heat-insulating panels 102 are engaged with hook-and-loop fasteners 110 on outer bag 101. Further, inner bag 103 is placed in outer bag 101 having heat-insulating panels 102 attached thereto, and hook-and-loop fasteners 112 are engaged with hook-and-loop fasteners 111 on respective heat-insulating panels 102 for assembly.
Frozen products or the like are housed in inner bag 103 of assembled cold-insulating vessel 100, lid 104 is placed over outer bag 101, and hook-and-loop fasteners 106 and 108 on lid 104 are engaged with hook-and-loop fasteners 107 and 109 on outer bag 101, respectively. Thus, the cold-insulating vessel is closed for delivery.
Cold-insulating vessel 100 disclosed in Japanese Patent Unexamined Publication No. 2003-112786 is collapsible not in use. In other words, not in use, inner bag 103 and four heat-insulating panels 102 are removed from outer bag 101, in a manner reverse to assembly, and removed heat-insulating panels 102 and collapsed inner bag 103 are housed inside of outer bag 101. Then, while outer bag 101 is being collapsed, lid 104 is placed on the bottom so as to face thereto. Belt 113 is placed over both ends of belts 105 to collapse the vessel.
In other words, cold-insulating vessel 100 disclosed in Japanese Patent Unexamined Publication No. 2003-112786 is made available for delivery as a box having heat-insulating property in use. Not in use, the vessel can be collapsed, delivered, and stored in a not bulky shape.
Delivery vehicles for use in delivery of foods or the like are roughly classified into freezer vehicles, refrigerator vehicles, cold-insulating vehicles, and room-temperature vehicles.
Among delivery vehicles, some are freezer and cold-insulating vehicles including both freezer and refrigerator in one vehicle, and some are those capable of switching the temperature of the one storage for a freezer and refrigerator so as to deliver all the products, from frozen foods to those stored at room temperature.
However, a vehicle having such a complex function is not typical. In delivery of frozen foods, it is common to place frozen products in a cold-insulating vessel with a cold-storage agent and deliver the cold-insulating vessel using a freezer vehicle.